Research On Hybrid Si/Organic Heterojunction Solar Cells By Micro/Nano-structure

Silicon(Si)/PEDOT:PSS hybrid solar cells have the dual advantages of inorganic and organic materials,which attracts the interest of researchers.With the development of research,the power conversion efficiency(PCE)and stability of this solar cells have been greatly improved.The PCE of Si/PEDOT:PSS hybrid solar cells has reached 16.1%with pyramid arrays and back passivation structure.In this paper,Si/PEDOT:PSS hybrid solar cells are taken as the research object.The research work is focused on the film-forming properties of PEDOT:PSS on silicon-based surface,passivation materials on silicon back surface and the Si substrate thinning.It has a certain meaning for the preparation of high-quality Si/PEDOT:PSS hybrid solar cells.We propose ethanol-induced pyramid arrays and gas-assisted silicon nanowire arrays to solve the problem of PEDOT:PSS film formation on silicon surface with micro-nano structure.The method of ethanol-induced film formation is based on the infiltration of different kinds of liquids on silicon surface,using ethanol with good infiltration as the inducing layer to induce poor infiltration PEDOT:PSS solution,so that PEDOT:PSS solution can achieve good contact effect on silicon surface;Gas-assisted method is based on the principle of the difference between internal and external pressure,under the action of pressure,PEDOT:PSS solution is directly pressed into the hole to increase the contact between the solution and the silicon surface.These two methods do not damage the properties of the PEDOT:PSS solution,and have the characteristics of simple and low-cost.The PCE of solar cells prepared by these two methods has been significantly improved.After optimizing the film-forming properties of PEDOT:PSS,and the wide-band gap metal semiconductor oxide was used as passivation material for the back surface of Si/PEDOT:PSS hybrid solar cells.Zinc oxide(ZnO)and tin oxide(SnO2)passivation films were successfully prepared by solution deposition at room temperature,and their mechanisms were studied.The existence of Si-O-Sn bond and the Ohmic contact between Si and Sn0?are proved.The optimal direction of electronic transmission between Si-O-Sn bond is calculated by the density functional theory(DFT).In addition,the ultrathin flexible silicon substrates with adjustable thickness of 2-30?m were successfully prepared by alkaline solution thinning method.Silicon nanowire arrays on ultra-thin silicon substrates were fabricated by metal-assisted etching and this substrate still was flexible.It is proved that the ultrathin silicon substrates with silicon nanowire arrays have reducing reflection and increasing transmission.